Dialkyl tin dialkoxide compounds and tetraalkyl dialkoxy distannoxane compounds are extremely useful as catalysts such as ester synthesis catalysts, carbonic acid ester synthesis catalysts, transesterification reaction catalysts and silicone polymer or urethane curing catalysts. In particular, in addition to carbonic acid esters being used as additives such as gasoline additives for improving octane value and diesel fuel additives for reducing particle levels in exhaust gas, these useful compounds are also used as alkylation agents, carbonylation agents or solvents and the like during synthesis of polycarbonates, urethanes, pharmaceuticals, agricultural chemicals and other organic compounds, or as lithium battery electrolytes, lubricating oil raw materials and raw materials of deoxygenating agents for rust prevention of boiler pipes. Dialkyl tin dialkoxide compounds and tetraalkyl dialkoxy distannoxane compounds are particularly attracting attention as synthesis catalysts. For example, Patent document 1 (International Publication No. WO 2003/055840) discloses a process for producing a carbonic acid ester comprising reacting an organometallic compound containing dialkyl tin dialkoxide with carbon dioxide followed by thermal decomposition of the formed addition product.
Various methods are known for producing dialkyl tin dialkoxide compounds and tetraalkyl dialkoxy distannoxane compounds.
For example, Patent document 2 (U.S. Pat. No. 5,545,600) discloses a process comprising carrying out a dehydration reaction on a dialkyl tin oxide and an alcohol and removing the resulting low boiling point component that contains water from the reaction liquid. This reaction is presumed to be a sequential equilibrium reaction accompanying dehydration as shown in formulas (1) and (2) below, and in order to obtain dialkyl tin dialkoxide at high yield, the dialkyl tin dialkoxide is produced while extracting the water formed by each dehydration reaction outside the system. Moreover, since this reaction is disadvantageous in terms of energy, it is necessary to carry out the reaction for a long time at a high temperature (for example, 180° C.), and there are cases in which thermal denaturation reactions occur in the products in the form of dialkyl tin dialkoxide compounds and tetraalkyl dialkoxy distannoxane compounds due to this heating for a long period of time at high temperatures. Since the dialkyl tin compound is a solid, there are cases in which handling difficulties occur during production by a continuous process.

(wherein each of R and R′ independently represents an alkyl group.)

(wherein each of R and R′ independently represent an alkyl group.)
In addition, Non-Patent document 1 (Journal of Chemical Society, p. 740, 1964) discloses a process for producing diethyl tin dibutoxide by reacting diethyl dichloro tin and sodium butoxide. In this reaction, since a byproduct in the form of sodium chloride is formed as a solid, the liquid after the reaction is in the form of a slurry, thus resulting in the possibility of handling difficulties when purifying the tin compound and the like.
On the other hand, Patent document 3 (International Patent Publication No. WO 2008/044575) describes a process in which a deactivated composition of a tin catalyst formed in the production process of carbonic acid ester is regenerated and again used as a catalyst in the production of carbonic acid ester. This regeneration process produces a dialkyl tin compound by heat-treating a compound produced by reacting a composition containing a deactivated form of a dialkyl tin alkoxide compound formed in the production process of carbonic acid ester with acid and/or acid anhydride, and the dialkyl tin compound is further regenerated to a dialkyl tin alkoxide compound.